The present invention relates to an apparatus and method for processing metal and, more particularly, to an apparatus and method of manufacturing sheet metal having regions of expanded metal and regions of non-expanded metal.
Expanded sheet metal is available in a wide range of patterns and gauges and can be made from several readily available metals or metal alloys with little or no metal loss during manufacturing. Expanded sheet metal is used in a wide variety of applications, including for use as filters, screens, grates, fencing, gutter protectors, battery plates, and other industrial or commercial applications.
One of the benefits of expanded sheet metal is that it is stronger per pound and lighter per foot than non-expanded sheet metal. Another benefit is the fact that expanded sheet metal is gas or fluid permeable.
Conventionally, the process of creating expanded sheet metal is accomplished by creating slits or cuts in a piece of solid sheet metal and then expanding or stretching the metal to create the plurality of openings or apertures therein. The process of expanding or stretching the sheet metal may be performed by stretching the metal in the direction of feed, opposite to the direction of feed, or lateral to the direction of feed. Such expanding of the sheet metal may be accomplished by inserting an object, such as a die, into the previously cut apertures and/or by stretching or pulling the metal from an edge or end of the sheet.
For some applications, it would be desirable to have regions or strips of non-expanded sheet metal included between regions of expanded sheet metal. The reasons for having such regions or strips of non-expanded metal are many. For example, it is often necessary to weld two different pieces of expanded sheet metal together to create longer pieces or to create three-dimensional shapes, such as cylindrical filters. For such applications, it is much easier and creates a stronger bond to weld two non-expanded metal regions together rather than to attempt to weld a region of expanded sheet metal to a non-expanded region or to another region of expanded sheet metal.
Typically, the inclusion of regions or strips of non-expanded sheet metal on a larger piece of sheet metal being expanded are restricted to the fixed arrangement of slit cutters along the processing path or, if the slit cutters are mounted to a roller, along the roller surface. Thus, the size, shape, spacing, and frequency of occurrence of regions of non-expanded sheet metal on a larger piece of sheet metal that is being expanded are generally fixed by virtue of discrete spaces between the cutting implements along the processing path or around the roller. Further, there is no capability to vary size, shape, spacing or frequency of the regions of non-expanded sheet on a particular piece of sheet metal being processed.
As can be appreciated, there is a continuing need for an improved metal expanding apparatus and methodology for manufacturing expanded sheet metal having regions of non-expanded sheet metal therein for use in a wide variety of applications.
There is also a continuing need for such an improved metal expanding apparatus and methodology for controlling the length of the expanded metal regions and/or the frequency of the non-expanded metal regions on a sheet of sheet metal.
There is a further continuing need for such an improved metal expanding apparatus and methodology, which is capable of creating regions of non-expanded sheet metal interspersed with regions of expanded sheet metal which are not defined solely by the discreet spaces or pre-positioning of each cutting implement.
The present invention meets one or more of the above-referenced needs, and potentially other needs not set forth above, as will be described herein in greater detail.
The present invention relates generally to an apparatus and method for processing metal and, more particularly, to an apparatus and method of manufacturing sheet metal having regions of expanded metal and regions of non-expanded metal
In particular, a first aspect of the invention is directed toward an apparatus for creating expanded and non-expanded regions on a sheet of sheet metal that includes a programmable controller, a feeder adapted to receive the sheet and responsive to the controller for incrementally advancing the sheet along a processing path, a cutter/expander positioned along the processing path and adapted to receive the sheet from the feeder, the cutter/expander responsive to the controller for generating a row of expanded metal apertures between each incremental advance of the sheet, the apertures in alternating rows being laterally offset from each other, each incremental advance of the sheet by the feeder having a first length when creating a respective expanded region of the sheet and a second length greater than the first length when creating a respective non-expanded region of the sheet.
In a feature of the apparatus, the controller is a computer having computer-readable instructions installed therein.
Preferably, the feeder comprises a pair of rollers and a feed motor for driving the rollers. Such feed motor is preferably a servo motor. Further, the rollers advance the sheet by means of pressure applied to the sheet or by means of frictional force applied to the sheet.
In an embodiment, the cutter/expander comprises an upper and a lower die and the sheet advances between the two die. Preferably, the die are offset from each other in the direction of the processing path. In an aspect of the invention, the upper die comprises a mounting arm and a plurality of pattern cutters. Preferably, the upper die is selectively movable perpendicular to the plane of the sheet between a disengaged and an engaged position, each respective row of apertures being generated by the pattern cutters when the upper die moves from the disengaged position to the engaged position.
In yet a further feature, the upper die is selectively moveable parallel to the plane of the sheet between a first cutting position and a second cutting position laterally offset from the first cutting position. Additionally, the cutter/expander further comprises a cam assembly and a cam motor for driving the cam assembly, the cam assembly controlling movement of the upper die between the first and second cutting positions, the upper die being in the first position when creating a first row of apertures and in the second position when creating a second row of apertures adjacent to the first row whereby the apertures in adjacent rows are laterally offset from each other.
In a preferred embodiment, the resulting expanded metal region has a mesh pattern in appearance.
In yet another aspect of the invention, a method for creating expanded and non-expanded regions on a sheet of sheet metal includes the steps of advancing the sheet a first predetermined distance along a processing path to define a first respective non-expanded metal region, creating a respective expanded metal region which includes the sub-steps of generating a first row of expanded metal apertures across the sheet, advancing the sheet a second predetermined distance along the processing path, and generating a second row of expanded metal apertures across the sheet, the first and second row of apertures being laterally offset from each other, and then the step of advancing the sheet a third predetermined distance along the processing path to define a second respective non-expanded metal region.
In a preferred embodiment, the second predetermined distance is shorter than the first and third predetermined distances. In one preferred embodiment, the first predetermined distance is the same as the third predetermined distance. In another preferred embodiment, the first predetermined distance is different from the third predetermined distance.
In yet another preferred embodiment, the steps of generating the rows of expanded metal apertures includes simultaneously slitting and stretching selected locations across the sheet.
In yet a further embodiment, the step of creating the respective expanded metal region further includes, after the step of generating the second row of expanded metal apertures, again advancing the sheet the second predetermined distance along the processing path and repeating a plurality of times the steps of generating the first row of expanded metal apertures, advancing the sheet the second predetermined distance, generating the second row of expanded metal apertures, and again advancing the sheet the second predetermined distance.